PNITER8ITY  OF   CALIFOBgIA   PUBLICATIONS 

COLLEGE  OF  AGRICULTURE 

AGRICULTURAL  EXPERIMENT  STATION 

BERKELEY,  CALIFORNIA 


RICE    IRRIGATION   MEASUREMENTS 

AND   EXPERIMENTS 

IN   SACRAMENTO  VALLEY 

1914-1919 

By  FRANK   ADAMS 


BULLETIN  No.  325 

September,  1920 


UNIVERSITY  OF  CALIFORNIA  PRESS 

BERKELEY 

1920 


David  P.  Barrows,  President  of  the  University. 

EXPERIMENT  STATION  STAFF 

HEADS  OF  DIVISIONS 

Thomas  Forsyth  Hunt,  Dean. 

Edward  J.  Wickson,  Horticulture  (Emeritus). 

Walter  Mulford,  Forestry,  Director  of  Resident  Instruction. 

C.  M.  Haring,  Director  of  Agriculture  Experiment  Station;  Veterinary  Science. 

B.  H.  Crocheron,  Director  of  Agricultural  Extension. 
Hubert  E.  Van  Norman,  Vice-Director;  Dairy  Management. 

James  T.  Barrett,  Acting  Director  of  Citrus  Experiment  Station;  Plant  Pathology. 

William  A.  Setchell,  Botany. 

Myer  E.  Jaffa,  Nutrition. 

Ralph  E.  Smith,  Plant  Pathology. 

J.  Eliot  Coit,  Citriculture. 

John  W.  Gilmore,  Agronomy. 

Charles  F.  Shaw,  Soil  Technology. 

John  W.  Gregg,  Landscape  Gardening  and  Floriculture. 

Frederic  T.  Bioletti,  Viticulture  and  Fruit  Products. 

Warren  T.  Clarke,  Agricultural  Extension. 

John  S.  Burd,  Agricultural  Chemistry. 

Charles  B.  Lipman,  Soil  Chemistry  and  Bacteriology. 

Ernest  B.  Babcock,  Genetics. 

Gordon  H.  True,  Animal  Husbandry. 

Fritz  W.  Woll,  Animal  Nutrition. 

W.  P.  Kelley,  Agricultural  Chemistry 

H.  J.  Quayle,  Entomology. 

Elwood  Mead,  Rural  Institutions. 

H.  S.  Reed,  Plant  Physiology 

L.  D.  Batchelor,  Orchard  Management. 

J.  C.  Whitten,  Pomology. 

Frank  Adams,  Irrigation  Investigations. 

C.  L.  Roadhouse,  Dairy  Industry. 
R.  L.  Adams,  Farm  Management. 

F.  L.  Griffin,  Agricultural  Education. 
John  E.  Dougherty,  Poultry  Husbandry 
W.  B.  Herms,  Entomology  and  Parasitology. 
L.  J.  Fletcher,  Agricultural  Engineering. 
Edwin  C.  Voorhies,  Assistant  to  the  Dean. 

division  of  irrigation  investigations 
(In  cooperation  with  Bureau  of  Public  Roads,  U.  S,  Department  of  Agriculture.) 

Frank  Adams.  F.  J.  Veihmeyer. 

S.  H.  Beckett.  II.  A.  Wadsworth. 


RICE   IRRIGATION   MEASUREMENTS   AND 
EXPERIMENTS   IN   SACRAMENTO  VALLEY 

1914-1919 

By  FKANK  ADAMS 


CONTENTS 

PAGE 

Cooperation 48 

Measurements  of  Use  of  Water 48 

Comments  on  Duty  of  Water  Tables 50 

Evaporation 56 

Experiments  at  Biggs  and  Norman 58 

Rice  Growing  and  Alkali  Injury 65 

Irrigation  and  Water  Grass 66 

Summary 66 

Appendix , 69 


In  May,  1917,  this  station  published  a  bulletin*  describing  Califor- 
nia rice  irrigation  practice,  and  methods  of  preparing  land  for  rice 
irrigation,  and  also  giving  results  of  measurements  of  the  amounts 
of  water  used  in  1916  on  eighteen  typical  Sacramento  Valley  rice 
fields,  and  of  cooperative  experiments  in  rice  irrigation  from  1914  to 
1916  conducted  at  the  Biggs  Rice  Field  Station.  Further  measure- 
ments of  use  of  water  were  made  in  1917  and  1918,  and  the  experi- 
ments at  Biggs  have  been  continued  through  1919.  In  addition,  the 
Biggs  experiments  were  duplicated  during  1918  and  1919  on  a  differ- 
ent type  of  soil  on  the  west  side  of  Sacramento  Valley,  on  the  Spalding 
Ranch,  near  Norman.  This  brief  supplementary  bulletin  has  been 
prepared  to  summarize  and  discuss  both  the  earlier  and  later  meas- 
urements and  experiments.  To  the  extent  available,  also,  gross  meas- 
urements of  use  of  water  on  rice  fields,  taken  from  operation  reports 
of  canal  companies  and  from  measurements  of  diversions  from  Sacra- 
mento River  in  1919  by  the  State  Department  of  Engineering,  in  part 
in  cooperation  with  this  station,  are  reported  in  the  appendix. 

*  Univ.  Calif.,  Coll.  Agr.,  Agr.  Exp.  Sta.  Bull.  279,  Irrigation  of  Rice  in  Cali- 
fornia, bv  Raich  D.  Robertson. 


50 


UNIVERSIY   OF   CALIFORNIA EXPERIMENT    STATION 


Table  II 

Summary  of  Measurements  of  Duty  of  Water  in  Rice  Irrigation  in  Sacra- 
mento Valley,  Seasons  of  1916,  1917,  and  1918,  Grouped  by  Soil  Types 
and  Arranged  in  Order  of  Depth  of  Water  Applied 


Soil  classification 


Number  of 

full  season 

observations 


Total 

area 

included  in 

observations, 

acres 


Average  net 
depth  of 

water 
applied, 

feet 


Average  area 

served  during 

full  season  per 

cu.  ft.  per 

sec,  acres 


Capay  clay 

Willows  clay  adobe 

Willows  clay 

Stockton  clay  adobe 

Sacramento  clay 

Tehama  clay  loam  and  clay 

Vina  clay  loam 

Willows  loam  and  clay  or  clay  adobe 

Madera  clay  loam,  etc 

Willows  loam 

San  Joaquin  loam 

Total  or  average 


2 
7 
7 
12 
4 
2 
1 
2 
1 
2 
3 


355 

8,477 

5,057 

2,877 

4,653 

267 

302 

71 

172 

122 

51 


3.94 

4.22 


9.38 
10.94 


81 
72 
70 
60 
59 
43 
37 
37 
37 
36 
30 


43 


22,404 


4.89 


66 


COMMENTS    ON     DUTY    OF    WATER    TABLES 

The  chief  factors  that  usually  affect  and  determine  the  duty  of 
water  in  irrigation  of  orchards  or  field  crops  in  any  given  locality — 
openness  of  the  soil  to  receive  and  its  ability  to  absorb  water,  crop, 
preparation  of  the  land  for  irrigation,  slope  of  land,  irrigating 
"head"  or  stream  available,  length  of  growing  season,  and  care  with 
which  water  is  applied — affect  and  determine  the  duty  of  water  in  rice 
irrigation  in  somewhat  different  measure. 

In  the  first  place,  for  best  results,  rice  must  have  sufficient  water, 
in  "heads"  or  streams  of  sufficient  size,  to  permit  of  one  initial  flood- 
ing five  to  ten  inches  deep  over  the  entire  area  and  three  to  six  flush- 
ings to  keep  the  soil  fairly  moist  during  germination  and  prior  to 
beginning  of  the  submergence  period;  that  is,  for  from  40  to  50  days, 
or  longer,  depending  upon  the  growing  weather  during  this  period 
and  upon  how  well  the  rice  has  been  seeded.  In  16  cases  out  of  the 
43  listed  in  table  I  this  preliminary  irrigation  period  exceeded  50 
days.  Excepting  during  the  period  of  beginning  submergence  and 
bringing  the  submergence  to  the  required  depth,  the  period  of  initial 
flooding  is  the  time  of  largest  need  if  the  irrigation  is  to  be  accom- 
plished satisfactorily. 


Bulletin  325  RICE   irrigation   MEASUREMENTS  51 

Second,  the  crop  must  be  kept  submerged  from  about  30  days, 
more  or  less,  after  emergence  of  the  plants  above  the  ground  until 
the  crop  has  been  made,  ranging  from  about  90  days  for  the  earlier 
maturing  varieties  to  about  110  to  130  days,  or  more  if  the  season  is 
cold,  in  the  case  of  the  Wataribune  variety  that  has  been  so  largely 
grown  in  California.  Obviously,  under  any  given  condition  of  soil 
and  preparation,  the  shorter  this  period  of  submergence  the  smaller 
the  total  quantity  of  water  used  during  the  season. 


Fig.  1. — First  flooding  of  a  new  rice  field  after  seeding.     Difference  in  elevation 
between  contours  or  cheeks  is  about  three  inches. 

Third,  under  any  given  condition  of  flushing  and  submergence,  it 
is  clear  that  rice  soil  will  require  water  in  direct  proportion  to  its 
imperviousness.  From  a  water  standpoint,  therefore,  that  soil  is  most 
satisfactory  for  rice  growing  that  loses  the  least  water  by  percolation 
through  it;  and  that  soil  will  show  the  lowest  duty  (the  largest  use) 
which,  because  of  its  loamy  texture,  permits  the  most  water  to  pass 
through  it  and  into  the  subsoil. 

Fourth,  the  near  proximity  of  deep  drains  and  also  poorly  made 
outside  levees  exert  a  far  greater  influence  on  water  duty  in  rice  grow- 
ing than  in  the  case  of  other  crops,  due  to  the  longer  period — 3  to  4 
months — the  irrigation  water  is  held  on  the  land  during  the  sub- 
mergence period;  and,  furthermore,  evaporation  is  a  greater  factor 
than  with  other  crops. 


52  UNIVERSIY   OF   CALIFORNIA EXPERIMENT   STATION 

Finally,  limited  observations  indicate  that  instead  of  requiring  a 
more  careful  use  of  water  as  in  the  case  of  ordinary  cultivated  crops, 
alkali  lands  utilized  for  rice  growing  require  a  somewhat  greater 
quantity  than  lands  free  from  alkali  because  of  needing  more  frequent 
irrigations  during  the  pre-submergence  period  and  of  the  further 
need  of  more  constant  circulation  of  water  through  the  checks  to 
carry  off  the  alkali  washed  out  from  the  surface  soil. 

Thus,  in  rice  irrigation  the  amount  of  water  used — the  duty  of 
water — needs  to  be  considered  from  a  standpoint  quite  different  from 
the  standpoint  of  orchard  or  field  crop  irrigation.  Excepting  during 
the  period  prior  to  submergence,  neither  the  capacity  of  the  soil  to 
receive  and  absorb  water  in  single  irrigations,  nor  the  length  of  irri- 
gation runs,  nor  even  the  surface  preparation  of  the  land  will  govern 
the  total  seasonal  use  as  much  as  the  imperviousness  of  the  soil  during 
submergence,  the  ability  of  the  outside  levees  to  retain  water,  the 
length  and  warmth  of  growing  season,  and  the  maturing  period  of 
the  variety  grown.  With  the  return  of  a  normal  price  for  rice,  the 
cost  of  water  will  also  be  a  governing  factor  that  at  present  is  apt  to 
be  lost  sight  of. 

Table  I  is  particularly  instructive  in  showing  the  wide  variation  in 
use  within  the  different  soil  classifications.  In  practice  newly  pre- 
pared and  seeded  fields  require  more  water  than  during  the  one  to 
three  subsequent  seasons  rice  is  grown  before  resting  the  land.  This 
obviously  is  due  to  the  settling  of  the  levees,  particularly  the  outside 
levees,  during  and  after  the  first  season,  and  also  to  the  compacting 
of  the  surface  soil  after  the  deeper  plowing  usually  given  when  the 
field  is  first  seeded  or  during  the  seasons  the  fields  are  fallowed  to 
get  rid  of  water  grass.  This  is  borne  out  in  numerous  instances 
included  in  the  table  as  may  be  seen  by  comparing  use  on  the  same 
fields  for  different  seasons.  Other  factors,  such  as  a  more  plentiful 
water  supply  the  subsequent  seasons,  may,  however,  alter  this, 
although  other  things  being  equal,  the  rule  holds  true. 

Another  interesting  fact  brought  out  by  table  I  is  the  consider- 
able variation  in  the  full  length  of  the  growing  season,  the  shortest 
shown  being  135  and  the  longest  189  days. 

Crop  yields,  not  included  in  the  table,  were  obtained  in  the  case 
of  all  of  the  fields  listed  and  these  have  been  scrutinized  for  any 
definite  relation  they  may  have  to  the  quantity  of  water  used.  Since 
water  grass,  however,  is  a  governing  factor  in  yields  of  rice,  given 
ample  water,  and  since  this  pest  was  present  more  or  less  in  all  second 
and  third  year  fields  under  observation,  no  clear  relation  was  found 


Bulletin  325  RICE  irrigation  measurements  53 

except  where  there  was  a  definite  shortage  of  water.  But  this  is 
clear  from  the  crop  data:  The  best  yields  were  not  always  obtained 
where  the  most  water  was  used,  nor  the  poorest  yields  where  the  least 
was  used,  but  generally  speaking,  just  the  contrary.  For  instance,  of 
nine  fields  producing  40  sacks  or  more  per  acre,   one  used  under 

4  feet  in  depth,  three  used  between  4  and  5  feet,  two  used  between 

5  and  5.5  feet,  one  (with  a  large  drain  adjacent)  used  7.69  feet,  one 
8.13  feet,  and  one  9.07  feet;  while  of  six  fields  producing  under  20 
sacks  per  acre,  four  received  gross  applications  in  excess  of  12  feet 
in  depth,  the  other  two  in  excess  of  7  feet  in  depth.  Four  of  the  fields 
having  this  low  yield  and  excessive  use  had  loam  soils;  one,  however, 
with  a  yield  of  only  17  sacks,  was  damaged  by  water  grass  and  ducks. 

The  regrouping  of  the  data  by  soil  classifications,  as  presented  in 
table  II,  makes  the  fact  clear  that  the  best  duty  of  water  in  rice  irri- 
gation in  Sacramento  Valley,  so  far  as  observations  have  gone,  is 
found  on  the  clays  and  clay  adobes  of  the  Capay,  Willows,  Stockton, 
and  Sacramento  series.  So  far  as  water  controls,  therefore,  the  data 
presented  indicate  that  over  long  periods  the  permanent  rice  growing 
industry  in  Sacramento  Valley  will  mainly  be  found  on  these  soils. 
The  rapid  encroachment  on  the  unregulated  flow  of  water  in  Sacra- 
mento Valley,  especially  of  Sacramento  River,  has  already  made  the 
scarcity  of  summer  water  the  limiting  factor  in  rice  growing,  and  it 
is  obvious  that  those  soils  will  most  likely  be  retained  in  this  crop  that 
require  the  least  water  for  successful  rice  culture. 

While  measurements  on  a  number  of  fields,  such  as  are  listed 
above,  are  necessary  to  ascertain  the  actual  use  of  water,  actual 
requirements  can  be  more  satisfactorily  determined  on  a  few  fields 
where  satisfactory  physical  conditions  are  present  and  where  water 
is  used  without  waste.  At  least  one  entirely  satisfactory  field  is 
included  in  the  table  in  the  E.  L.  Adams  field  of  39.5  acres,  which 
adjoins  the  Biggs  Rice  Field  Station,  and  on  which  measurements 
were  made  from  1914  to  1917.  This  field  was  properly  handled 
throughout,  kept  free  from  water  grass,  and  ample  water  used  but 
none  wasted.  The  principal  data  for  this  field  are  regrouped  in 
table  III  below  with  additional  data  added.  This  indicates  better  than 
any  other  field  under  observation  what  can  be  accomplished  on  such 
soil  as  Stockton  clay  adobe,  which  comprises  a  large  area  of  rice 
soil  in  Sacramento  Valley,  and  taken  in  connection  with  the  data  for 
the  other  fields  listed,  justifies  the  conclusion  that  on  the  best  rice 
soils,  an  annual  use  of  five  acre-feet  per  acre  is  sufficient. 


54 


UNIVERSIY   OF   CALIFORNIA EXPERIMENT    STATION 


Table  III 

Results  of  Measurements  of  Use  of  Water  on  E.  L.  Adams  Rice  Field,  Near 
Biggs,  1914-1917.     Area,  39.5  Acres;  Soil,  Stockton  Clay  Adobe. 


Full  irrigation 
season 

Net  depth 

of  water 

applied, 

feet 

Average  area  served  per  cu. 
foot  per  second,  acres 

Yield 
per  acre 

Year 

From- 

To- 

Period  of 
submergence 

Whole 
season* 

in  sacks 
averaging 
100  pounds 

1914 
1915 
1916 

1917 

Apr.     29 
Apr.     21 
Apr.     13 
Apr.     11 

Oct.      12 
Oct.       1 
Sept.    30 
Sept.    21 

4.65 
4.87 
4.27 
4.37 

68 
66 
70 
62 

56 
51 
56 
51 

60 
45 
39 
39 

Averag 

e 

4.53 

66 

53 

46 

*Only  days  water  used  during  pre-submergence  period  considered  in  computing 
whole  season. 

Note.' — The  amount  of  water  used  on  this  field  was  not  measured  in  1918  but  it 
continued  in  crop  and  yielded,  the  fifth  season,  36  sacks  per  acre.  Such  a  record 
would  not  have  been  possible,  however,  without  good  preparation  of  the  land  in  the 
first  instance,  careful  use  of  water  without  waste,  and  keeping  the  field  free  from 
water  grass. 

It  is  not  only  the  annual  depth  of  water  required  for  rice  that 
needs  to  be  considered,  because  it  is  only  after  the  rice  fields  have 
been  brought  to  full  submergence  that  the  use  is  fairly  uniform. 
In  a  measure,  the  "peak"  needs  during  the  initial  flooding  following 
seeding  and  during  the  period  submergence  is  being  brought  to  the 
required  depth  will  govern  the  quantity  that  must  be  available,  at 
times,  to  individual  users  as  well  as  under  entire  systems.  The  figures 
in  columns  9,  10,  and  11  in  table  I  and  the  figures  in  columns  5  and  6 
in  table  III  give  some  information  on  this  question.  These  show  a 
use  during  the  submergence  period  ranging  from  1  cubic  foot  per 
second  for  each  18  acres  to  1  cubic  foot  per  second  to  each.  74  acres 
irrigated.  Columns  10  and  11  in  table  I  show  average  use  during 
the  whole  season  from  the  beginning  of  the  first  irrigation  through 
the  submergence  period;  columns  5  and  6  in  table  III  show  use  with 
the  whole  season  considered  only  as  including  the  entire  submergence 
period  and  the  days  during  the  pre-submergence  period  water  was 
actually  used  on  the  field.  Fully  satisfactory  data  for  computing  the 
demand  of  systems  on  the  basis  of  acres  served  per  cubic  foot  per 
second  are  not  available,  but  the  need  seems  to  average  1  cubic  foot 
per  second  to  each  50  to  60  or  more  acres  irrigated,  with  the  prob- 
ability that  the  average  area  served  per  cubic  foot  per  second  will  be 


Bulletin  325 


RICE    IRRIGATION    MEASUREMENTS 


55 


increased  for  large  systems  as  fields  are  left  fallow,  or  cultivated  to 
other  crops  to  eliminate  water  grass. 

The  demand  of  individual  fields  measured  in  acres  served  per  cubic 
foot  per  second  can  be  fairly  well  computed  from  the  data  at  hand, 
and,  for  the  pre-submergence  period,  from  irrigation  needs  in  general 
irrigation  practice.  Figures  in  columns  5  and  6  in  table  III  are 
probably  representative  of  needs  on  well  handled  fields  where  the  soil 
is  of  the  adobe  or  clay  type  most  suitable  for  rice  growing.  These 
show  an  average  use  for  the  submergence  period  of  about  66  acres 
per  cubic  foot  per  second  and  for  the  whole  season  of  about  53  acres 
per  cubic  foot  per  second.  More  detailed  data  showing  use  by  months 
are  presented  in  table  IV  for  eleven  fields.  The  examples  are  not 
sufficiently  alike  in  matter  of  practice,  however,  to  warrant  definite 
comparisons  or  exact  conclusions,  although  they  do  indicate  variation 
in  individual  use. 

Water  requirements  of  rice  during  the  initial  flooding  to  start 
germination  are,  for  individual  fields,  in  excess  of  requirements  during 
either  the  remainder  of  the  pre-submergence  period  or  during  sub- 

Table  IV 

Summary  of  Areas  of  Rice  Land  Served  Per  Cubic  Foot  of 

Water  Per  Second 


Owner  or 
grower 


Year 


Area 
irri- 
gated, 
acres 


Soil 


Average  area  served  per  cubic 
foot  per  second,  acres 


April 


May 


June 


July 


Aug. 


Sept. 


Evans  Bros 

Hardin  &  Scheeline. 


B.  E.  Crouch. 
E.  L.  Adams.. 


Moulton  Irrigated 

Lands 

Maupin  &  Emmons. 
Schell  &  Woodruff... 


E.  L.  Adams 

Mallon  &  Blevins. 


Spalding  Co 

Hardin-Purcell-Locher 


1916 

1916 

1916 
1916 

1917 
1917 
1917 

1917 

1918 

1918 
1918 


187 

133 

302 
39 

823 
115 
172 

71 

5909 

1880 
150 


Stockton  clay 

adobe 
Tehama  clay 

loam  and  clay 
Vina  clay  loam 
Stockton  clay 

adobe 
Sacramento 

clay 
Willows  clay 
Madera  clay 

loam 
Stockton  clay 

adobe 
Willows  clay 

adobe 
Willows  clay 
Willows  clay 

adobe 


83 
36 
14 


27 

40 

21 
12 

45 
55 
36 

14 

95 

90 

27 


27 

50 

25 
71 

45 
55 

27 

19 
54 

83 

27 


20 

33 

29 
71 

37 
53 

28 

53 

50 

55 
29 


27 

42 

33 
71 

41 
62 
31 

67 

59 

59 
24 


24 

43 

42 
83 

40 
71 
55 

83 

55 

77 
25 


56  UNIVERSIY   OF   CALIFORNIA EXPERIMENT   STATION 

mergence.  From  4  inches  to  6  inches  in  depth  is  necessary  to  provide 
an  adequate  initial  flooding,  but  not  over  1  to  2y2  inches  in  depth 
should  be  required  in  checks  of  normal  size  for  subsequent  pre-sub- 
mergence  floodings.  On  this  basis  the  "peak"  pre-submergence  duty 
per  cubic  foot  per  second,  for  individual  fields,  will  vary  from  about 
30  to  40  acres  with  a  6-inch  flooding  to  from  40  to  60  acres,  in  both 
cases  assuming  that  the  initial  flooding  of  the  entire  field  is  to  be 
accomplished  within  seven  to  ten  days,  which  about  conforms  to  normal 
requirements.  In  practice  a  minimum  irrigating  head  should  be  at 
least  2  cubic  feet  per  second  and  a  larger  head  is  desirable,  since 
general  irrigation  experience  has  taught  that  in  flooding  lands  large 
rather  than  small  heads  give  the  most  even  and  most  economical 
irrigation. 

EVAPORATION 

The  effect  of  evaporation  on  the  duty  of  water  in  rice  irrigations, 
already  referred  to  as  being  greater  than  with  other  irrigated  crops, 
is  the  factor  over  which  least  control  is  possible  and  probably  none 
practicable.  The  well-known  relation  between  evaporation  and  tem- 
perature suggests  that  within  certain  limits,  the  deeper  the  sub- 
mergence of  rice  fields  the  smaller  the  evaporation  rate.  For  instance, 
water  temperatures  taken  in  submergence  plots  on  the  Norman  experi- 
mental tract  July  25,  August  10,  September  1,  October  1,  1918, 
showed  a  wider  daily  variation  in  plots  submerged  2  inches  deep  than 
in  plots  submerged  either  4,  6,  or  8  inches  deep.  This  difference  is 
generally  most  marked  between  2-inch  and  4-inch  submergence,  being 
4  degrees  on  July  25,  8  degrees  August  10,  and  only  1  degree  on  Sep- 
tember 1  and  October  1.  The  full  data  for  these  dates  taken  from 
a  continuous  record  extending  from  July  25  to  October  1,  1918,  are 
included  in  table  V  below.  They  indicate  that  as  a  practical  matter 
any  attempt  through  reducing  the  depth  of  submergence  to  save  water 
by  decreasing  evaporation  is  not  likely  to  be  justified. 

Although  it  appears  that  evaporation  must  be  accepted  as  largely 
an  uncontrollable  factor  in  rice  irrigation,  it  is  in  a  way  a  measurable 
factor.  While  the  evaporation  from  a  rice  field  is  less  than  from  a 
free  water  surface,  owing  to  the  shading  by  the  rice  plants,  the  loss 
from  a  free  water  surface  gives  a  general  indication  of  the  loss  from 
the  latter.  Seasonal  records  are  available  for  the  Norman  experi- 
mental tract  for  1918  and  1919  and  for  the  Biggs  Rice  Field  Station 
for  1917  to  1919.  They  indicate  in  a  general  way  that  during  the 
four  principal  growing  months,  June  to  September,  which  roughly 
coincide  with  the  submergence  period,  the  evaporation  loss  reaches 
at  least  one-third  of  the  water  applied. 


Bulletin  325 


RICE    IRRIGATION    MEASUREMENTS 


57 


Table  V 

Variation  in  Water  Temperatures  in  Submerged  Rice  Plots  at  Norman,  1918, 

With  Different  Depths  of  Submergence.     Temperatures 

and  Variation  in  Degrees  Fahrenheit 


Depth 

Times 

of 

observation 

July  25 

August  10 

September  1 

October  1 

of 
submergence 

Water 
temper- 
ature 

Varia- 
tion 

Water 
temper- 
ature 

Varia- 
tion 

Water 
temper- 
ature 

Varia- 
tion 

Water 
temper- 
ature 

Varia- 
tion 

2  inches 
4  inches 
6  inches 
8  inches 

8  a.m. 
1  p.m. 
6  p.m. 

8  a.m. 
1  p.m. 
6  p.m. 

8  a.m. 
1  p.m. 
6  p.m. 

8  a.m. 
1  p.m. 
6  p.m. 

73 
96 

87 

72 
91 
88 

73 
90 

88 

72 
90 
88 

23 
19 
17 

18 

66 
90 

83 

68 
84 
84 

70 

85 
87 

70 

85 
86 

24 
16 
17 
16 

74 
89 
87 

75 
88 
89 

76 

86 
88 

77 
85 
87 

15 
14 
12 
10 

66 

75 
76 

66 

74 
75 

65 
73 
76 

65 
73 

76 

10 

9 

11 

11 

Table  VI 

Evaporation  Record  at  Rice  Experiment  Field,  Spalding  Ranch,  Norman, 
June  1  to  September  30,  1918  and  1919 


June 

July 

August 

September 

Total  4  mo. 

Year 

Period 

Inches 

Inches 

Inches 

Inches 

Inches 

Month 

12.02 

9.48 

6.04 

2.41 

29.95 

1918 

Max.  daily 

.49 

.43 

.27 

.12 

Min.  daily 

.35 

.26 

.11 

.07 

Month 

11.88 

10.70 

6.19 

3.22 

31.99 

1919 

Max.  daily 

.38 

.36 

.22 

.17 

Min.  daily 

.24 

.21 

.13 

.06 

Note. — Total  evaporation  June  1  to  October  27,  1918,  32.30  inches;  average  per 
day  .217  inch.  Total  evaporation  May  26  to  October  4,  1919,  34.42  inches;  average 
per  day,  .252  inch.     Evaporation  pan  20  inches  in  diameter  by  18  inches  deep. 


58 


UNIVERSIY   OF   CALIFORNIA EXPERIMENT   STATION 


Table  VII 

Evaporation  Record  at  Biggs  Rice  Field  Station  of  Bureau  of  Plant  Industry 

For  Seasons  of  1917,  1918,  and  1919.     Record  Furnished 

by  E.  L.  Adams  and  Jenkin  W.  Jones 


Year 

Period 

April 

May 

June 

July 

Aug. 

Sept. 

Oct. 

Total 
for 

period 
measur- 
ed 

Inches 

Inches 

Inches 

Inches 

Inches 

Inches 

Inches 

Inches 

1917* 
1918f 
1919§ 

Month 
Max.  daily 
Min.  daily 

Month 
Max.  daily 
Min.  daily 

Month 
Max  daily 
Min.  daily 

4.09 
.34 
.07 

6.11 
.39 
.08 

8. lit 
.57 
.32 

9.45 
.57 
.19 

12.22 
.69 
.15 

8.99 
.43 
.15 

10.11 
.41 

.22 

8.68 
.47 
.16 

9.69 
.41 
.18 

8.18 
.42 
.16 

7.03 
.42 
.06 

7.86 
.38 
.15 

6.16 
.31 
.06 

3.81 
.26 
.03 

5.50 
.32 
.47 

4.48 
.40 
.02 

4.25 
.20 
.02 

44.10 
44.33 
36.29 

*Record  covers  April  1  to  September  30  (28  days  in  April). 

fRecord  covers  May  13  to  October  31  (29  days  in  Oct.). 

+ Record  covers  one-half  month. 

§Record  covers  June  1  to  October  31. 

Note. — Evaporation  pan  72  inches  in  diameter  by  24  inches  deep. 


EXPERIMENTS    AT    BIGGS    AND    NORMAN 

Because  rice  is  a  relatively  new  crop  in  California  growers  have 
been  compelled  to  feel  their  way  in  the  matter  of  irrigation  on  the 
basis  of  such  knowledge  as  has  been  brought  from  the  South  and  from 
foreign  countries,  and  such  experience  as  has  been  gained  and  such 
study  as  has  been  possible  since  rice  growing  commenced  on  a  com- 
mercial scale  in  California  about  1912.  The  state  also  has  been  com- 
pelled, in  acting  on  permits  to  appropriate  water  for  the  irrigation 
of  rice,  to  reserve  final  judgment  as  to  the  water  needs  of  this  crop 
until  more  information  might  be  available. 

Aside  from  the  matter  of  the  proper  duty  of  water  in  the  irrigation 
of  this  crop,  it  has  been  important  that  the  proper  time  and  methods 
of  applying  the  water  be  known.  The  experiments  at  Biggs  and  at 
Norman,  already  referred  to,  have  made  some  progress  in  supplying 
this  fundamental  information  and  have  suggested  further  experiments 
it  is  important  to  undertake. 


Bulletin  325  RICE   irrigation   MEASUREMENTS  59 

As  outlined  in  the  previous  publication  of  this  station  on  rice 
irrigation,*  the  purpose  of  the  experiments  at  Biggs,  later  duplicated 
for  two  years  at  Norman,  has  been  to  determine  the  effect  of  varying 
the  dates  of  submergence  of  the  crop,  of  varying  the  depths  of  sub- 
mergence, of  not  giving  continuous  submergence  during  the  usual 
submergence  period,  of  slowly  changing  versus  stagnant  water,  and 
of  fluctuating  the  depth  of  submergence.  The  tests  at  Biggs  were 
made  on  one-fifth  acre  plots  during  1914,  1915,  1916,  1918  and  1919, 
and  on  one-tenth  acre  plots  during  1917,  in  which  year  the  original 
tract  was  fallowed.  The  tests  at  Norman  in  1918  and  1919  were  made 
with  one-fourth  acre  plots. 

The  soil  on  which  the  Biggs  experiments  were  conducted  is  the 
black  clay  adobe  (Stockton  clay  adobe)  typical  of  most  of  the  land 
utilized  for  rice  growing  around  Gridley,  Biggs,  Richvale  and  Nelson. 
The  soil  at  Norman  on  which  the  experiments  were  duplicated  in 
1918  and  1919  is  classified  as  Willows  clay  and  locally  known  as 
"goose  land."  Reporting  on  the  alkali  content  of  the  Norman  soils, 
Dr.  C.  B.  Lipman,  of  the  Division  of  Soil  Chemistry  and  Bacteriology 
of  the  College  of  Agriculture,  describes  them  as  representing  a  silty 
clay  loam  surface  soil  with  a  slightly  heavier  subsoil,  and  with  their 
physical  condition  rather  poor.  The  variation  in  alkali  content  (in  this 
case  largely  in  the  form  of  sodium  chloride  and  sodium  sulfate,  with 
traces  of  gypsum  and  sodium  carbonate,  or  "black  alkali")  ranged  in 
the  analyses  made  by  Dr.  Lipman  from  too  little  to  warrant  analysis  to 
1.15  per  cent ;  and  observations  in  the  field  during  the  growing  season 
indicated  an  even  stronger  alkali  content  in  patches  than  the  samples 
analyzed  showed.  Ground  water  stood  about  3  feet  below  the  surface 
at  the  beginning  of  the  season  in  1918  and  had  raised  about  6  inches 
by  the  end  of  that  season;  during  1919  the  fluctuation  was  between 
2.5  and  3.5  feet,  the  greater  depth  occurring  in  July  and  August. 
Because  of  the  great  variation  in  the  soil  at  the  Norman  station,  the 
plots  were  arranged  in  quadruplicate,  while  they  were  duplicated 
(excepting  in  1917)  at  Biggs.  The  location  of  the  Biggs  experiments 
was  on  the  Biggs  Rice  Field  Station  of  the  Bureau  of  Plant  Industry 
and  at  Norman  at  the  northern  end  of  the  Spalding  Ranch  about 
five  miles  south  of  "Willows. 

The  results  of  the  experiments  at  both  Biggs  and  Norman  are 
grouped  in  tables  VIII,  IX,  and  X  below. 


*  Univ.  of  Calif.  Coll.  of  Agr.,  Exp.  Sta.  Bull.  279. 


60 


UNIVERSIY   OF   CALIFORNIA EXPERIMENT    STATION 


Table  VIII 

Results  of  Experiments  at  Biggs  and  Norman  on  the  Effect  on  Yields  of 

Varying  the  Date  of  Submergence  of  Rice  Fields  After 

Emergence  of  the  Plants  Above  the  Ground. 

Depth  of  Submergence  6  Inches. 


Location 

Yields  of  rice  in  pounds  per  acre  with  different  dates  of  beginning 
submergence 

Year 

15  days  after 
emergence 

30  days  after 
emergence 

45  days  after 
emergence 

60  days  after 
emergence 

1914 
1915 
1916 
1917 
1918 
1919 
1918 
1919 

Biggs 
do 
do 
do 
do 
do 
Norman 
do 

4510 

3860 
3750 
4220 
3420 
1700 
3568 
2682 

5610 
4270 
4020 
4500 
4185 
2230 
3108 
2809 

5410 
4100 
3890 
4310 
3240 
2050 
2604 
2096 

5240 
3910 
3610 
4040 
4115 
1980 
1933 
1650 

Average  for  3 
Average  for  3 

3iggs 

3577 
3125 

4136 

2958 

3833 
2350 

3816 

Gorman 

1791 

Table  IX 

Results  of  Experiments  at  Biggs  and  Norman  on  the  Effect  on  Yields  of 
Varying  the  Depth  of  Submergence  of  Rice  Fields.     Submer- 
gence Begun  30  Days  After  Emergence. 


Location 

Yields  of  rice  in  pounds  per  acre  with  different  depth 

s  of  submergence 

Year 

2  inches 

4  inches 

6  inches 

8  inches 

1914 

Biggs 

5010 

5490 

5670 

5220 

1915 

do 

4030 

4290 

4510 

4400 

1916 

do 

3620 

3760 

3900 

3940 

1917 

do 

4260 

4440 

4520 

4480 

1918 

do 

4635 

4215 

4035 

4015 

1919 

do 

3000 

2990 

3050 

2710 

1918 

Norman 

2722 

3154 

3425 

3132 

1919 

do 

2452 

2275 

2747 

1876 

Average  for  BiVcs 

4092 

4197 

4281 

4127 

Average  for  Is 

Gorman 

2587 

2715 

3086 

2504 

Bulletin  325 


RICE    IRRIGATION    MEASUREMENTS 


61 


Table  X 

Results  of  Experiments  at  Biggs  and  Norman  on  the  Effect  on  Yields  of 
Slowly  Changing  Water,  Stagnant  Water,  No  Submergence, 
and  Fluctuation  of  Depth  During  Submergence.     Sub- 
mergence Begun  30  Days  After  Emergence 


Location 

Yields  of  rice  in  pounds  per  acre 

with  different  water  treatments 

Year 

Slowly  changing 
water;  6-inch 
submergence 

Stagnant  water; 
6- inch  sub- 
mergence 

No  submergence 

but  soil  kept 

moist 

Fluctuation  of 
depth  of  sub- 
mergence 

1914 

Biggs 

4790 

4940 

2440 

5290 

1915 

do 

4210 

3990 

2480 

4160 

1916 

do 

3460 

3800 

2100 

3690 

1917 

do 

4230 

4405 

2490 

4360 

1918 

do 

3615 

2550 

2860 

3625 

1919 

do 

3000 

2600 

1250 

2950 

1918 

Norman 

2670 

2504 

1800 

3187 

1919 

do 

2212 

1239 

2265 

2909 

Average  for  Bis-ers 

3884 

3714 

2270 

4012 

Average  for  I 

Gorman 

2441 

1871 

2033 

3048 

Time  of  submergence. — The  figures  for  Biggs  in  table  VIII  con- 
sistently showed  the  largest  yields  from  beginning  submergence  of 
the  rice  land  30  days  after  emergence  of  the  crop  above  the  ground; 
and  that  with  the  single  exception  of  1918,  beginning  submergence 
45  days  after  emergence  was  better  than  either  15  or  60  days  after 
emergence.  The  advantage  gained  by  beginning  submergence  30  days 
after  emergence  averaged  15  per  cent,  or  5%  sacks,  over  15-day  sub- 
mergence, but  only  about  8  per  cent,  or  about  3  sacks,  over  45-day 
and  60-day  submergence.  At  Norman,  however,  the  average  results 
seem  to  indicate  that  the  beginning  of  submergence  on  such  soils  as 
Willows  clay,  with  which  alkali  is  largely  associated,  can  best  be 
placed  nearer  to  15  days  after  emergence  than  30  days  after.  For 
1919,  it  is  to  be  noted,  the  larger  yield  at  Norman  resulted  from  begin- 
ning submergence  30  days  after  emergence,  as  at  Biggs;  and  by 
segregating  the  1919  records  according  to  whether  the  soil  should 
be  classified  as  "alkali"  or  "good,"  the  tendency  for  the  30-day  sub- 
mergence to  give  the  better  results  is  increased.  Nevertheless,  the 
average  in  favor  of  the  earlier  submergence  on  alkali  lands  is  not 
overcome  by  the  1919  results  at  Norman,  and  this  is  not  changed  even 
by  making  a  similar  segregation  for  1918.     Apparently  the  ruling 


62 


UNIVERSIY   OF   CALIFORNIA EXPERIMENT    STATION 


condition  is  the  alkali,  and  that  early  submergence  of  the  alkali  lands, 
by  earlier  reducing  the  alkali  concentrations  in  the  surface  soils,  gives 
a  protection  to  the  young  plants  that  is  not  needed  where  the  alkali 
is  not  present. 

In  further  analysis  of  the  results  presented  in  the  above  table  it 
should  be  noted  that  the  largest  advantage  of  30-day  over  15-day 
submergence  occurred  in  1914,  when  the  land  was  first  seeded  to  rice. 
While  this  is  a  suggestion  that  the  advantage  of  one  treatment  over 


Moist  soil     Submergence  Submergence  Submergence  Submergence    Fluctuating 
without  2  inches        4  inches         6  inches         8  inches      depth    of 

?    submergence        deep  deep  deep  deep         submergence 


Fig.  2. — Typical  stool  of  rice  from  experimental  plots  at  Norman,  1919.     These 
show  relative  growth  under  different  depths  of  submergence. 


another  is  likely  to  be  greatest  on  new  land,  one  experiment  is  not 
conclusive.  Probably  the  most  important  factor  to  determine  practice 
will  be  the  advantage  of  early  over  late  submergence  as  compared 
to  the  extra  cost  of  the  early  submergence.  Since  the  time  of  ripen- 
ing of  the  crop  apparently  is  not  greatly  affected  by  the  time  sub- 
mergence commences*  the  cost  advantage  of  the  15-day  or  30-day 
submergence  over  the  45-day  or  60-day  submergence,  where  alkali 
is  not  a  factor  requiring  the  early  submergence,  is  not  yet  demon- 
strated. 


*  For  instance,  in  1918,  which  is  typical,  the  plots  submerged  15  days  after 
emergence  matured  their  crop  only  4  days  in  advance  of  the  plots  receiving 
30-day,  45-day,  and  60-day  submergence. 


Bulletin  325 


RICE    IRRIGATION    MEASUREMENTS 


63 


Depth  of  submergence. — With  two  exceptions  at  Biggs — 1916  and 
1918 — the  experiments  with  depth  of  submergence  summarized  in 
table  IX  gave  the  best  yields  with  a  submergence  of  6  inches  through- 
out the  submergence  period.  But  the  increased  crop  over  the  next 
highest  plots  obtained  with  a  6-inch  submergence  ranged  from  less 
than  1  to  only  4  per  cent,  averaging  for  the  six  years  about  2  per  cent. 
For  the  two  years  at  Norman  the  6-inch  submergence  also  produced 
best,  with  an  average  increase  of  13  per  cent  above  the  4-inch  sub- 


30     days  lOO     days  120    days 

after     beginning        after     beginning        after    beginning 
submergence.  submergence.  submergence. 


Fig.  3. — Kepresentative  rice  plants  at  different 

submergence. 


stages  of  development  during 


mergence.  Expressed  in  sacks  of  rice  per  acre,  the  average  advantage 
of  the  6-inch  submergence  over  the  4-inch  submergence  was  .84  of  a 
sack  at  Biggs  and  3.71  sacks  at  Norman.  The  average  increase  for 
the  first  two  years  at  Biggs,  which  is  a  better  figure  with  which  to 
compare  the  2-year  average  at  Norman,  was  only  2  sacks  per  acre. 
While  these  experiments  seem  to  indicate  that  it  is  good  practice 
to  submerge  to  a  depth  of  6  inches,  the  small  increases  at  Biggs  raise 
the  question  as  to  whether  the  increased  cost  of  6-inch  over  a  4-inch 
submergence  is  justified  by  the  return.  This  increased  cost  should 
be  figured  both  in  money  for  extra  water  and  extra  labor  to  maintain 
the  deeper  submergence,  and  also  in  the  extra  water  which  the  state 
permits  the  irrigator  to  withdraw  from  the  stream.  The  13  per  cent 
increase  at  Norman  probably  justifies  the   6-inch  submergence,   the 


64  UNIVERSIY   OF   CALIFORNIA EXPERIMENT   STATION 

2  per  cent  increase  at  Biggs  probably  does  not.  A  more  complete 
determination  of  this  must  wait  on  further  intensive  experiments. 
Certainly  even  a  2-inch  submergence  made  a  more  creditable  showing 
than  might  have  been  expected.  In  1918  the  2-inch  submergence  gave 
by  far  the  best  yield  at  Biggs,  in  1919  it  gave  next  to  a  6-inch  sub- 
mergence at  Norman;  and  in  no  year,  either  at  Biggs  or  at  Norman, 
did  it  fail  to  give  within  12  per  cent  of  the  maximum  for  that  year, 
averaging  but  4  per  cent  below  the  average  maximum  at  Biggs — 
equivalent  to  1.79  sacks  per  acre — and  16  per  cent  below  the  maximum 
at  Norman — equivalent  to  5  sacks  per  acre. 

Stagnant  versus  changing  water. — The  normal  condition  in  the 
rice  checks  is  for  water  during  submergence  to  be  slowly  changing 
within  an  indefinite  area  between  the  inlet  of  the  water  and  the  gate 
or  gates  leading  to  the  next  lower  check,  but  with  a  considerable  por- 
tion of  each  check  stagnant  or  nearly  so.  The  relative  yields  under 
slowly  changing  and  stagnant  water  given  in  the  third  and  fourth 
columns  in  table  X  do  not  show  any  constant  advantage,  excepting 
in  the  case  of  the  Norman  experiments.  The  Biggs  results  show  the 
greater  yields  in  one-half  of  the  six  years  under  observation  to  fall 
under  each  treatment,  but  with  a  4%  per  cent  average  advantage, 
equivalent  to  1.70  sacks  per  acre,  with  the  slowly  changing  water. 
At  Norman  the  slowly  changing  water  gave  definitely  better  results 
each  year,  with  probably  an  abnormal  advantage  in  1919.  The  2-year 
period  at  Norman  is  of  course  too  short  for  definite  conclusion,  but 
the  presence  of  alkali  in  considerable  quantities  there,  taken  with  the 
appearance  of  the  plants  in  the  stagnant  and  slowly  changing  plots, 
indicates  that  on  alkali  soil  stagnant  water  during  submergence  is 
most  likely  to  be  injurious,  depending  on  the  amount  and  kind  of 
alkali  present.  Here  again  further  studies  are  necessary  for  a  final 
determination  of  the  matter. 

Fields  moist  but  with  no  submergence. — Column  5  in  table  X  seems 
definitely  to  make  clear  that  under  such  conditions  as  are  present  on 
the  Stockton  clay  adobe  at  Biggs,  merely  keeping  the  rice  fields  moist 
instead  of  flooded  during  the  usual  submergence  period  will  not  give 
fully  satisfactory  yields.  It  is  to  be  noted,  however,  that  excepting 
in  1919,  the  yields  under  the  "moist"  treatment  were  considerable, 
both  at  Biggs  and  at  Norman.  Apparently  California  conditions  may 
permit  of  some  commercial  yields  without  submergence,  although  to 
what  extent  this  will  prove  profitable  does  not  appear.  However,  the 
results  of  the  "moist"  treatments  were  not  always  satisfactory  from 
the  standpoint  of  the  quality  of  the  rice. 


Bulletin  325  RICE  irrigation   MEASUREMENTS  65 

Fluctuation  of  depth  of  submergence. — The  plan  of  fluctuating 
submergence  followed  in  these  experiments  was  to  hold  a  uniform 
depth  of  4  inches  to  6  inches  after  beginning  submergence  until  ' '  boot- 
ing" was  noticeable,  then  to  lower  the  depth  to  1%  to  2  inches  until 
the  first  heads  appeared,  finally  bringing  it  back  to  a  depth  of  4  to  6 
inches  until  the  rice  was  ready  for  draining.  This  plan  of  fluctuating 
depth  was,  however,  somewhat  altered  in  1918. 

As  compared  with  the  other  results  listed  in  table  X,  fluctuating 
the  depth  gave  the  better  yields.  As  compared  with  the  yields  with 
continuous  4-inch  or  6-inch  submergence  throughout  the  submergence 
period  as  listed  in  table  IX,  however,  the  yields  with  fluctuating 
depths  were  definitely  below  the  best  at  Biggs,  although  in  less 
measure  at  Norman.  Apparently  some  fluctuation,  as  frequently 
results  from  interruption  of  water  source,  is  not  markedly  injurious ; 
and  it  may  be  possible  that  further  experiments  will  show  conditions 
under  which  fluctuation  of  depth  will  be  advantageous,  especially 
if  California  rice  fields  come  to  have  insect  troubles  similar  to  those 
experienced  in  the  Southern  rice  fields.* 

RICE    GROWING    AND    ALKALI    INJURY 

The  well-known  injury  that  results  to  lands  from  rise  of  ground 
water,  with  attendant  damage  from  alkali,  will  in  time  automatically 
reduce  the  area  that  can  profitably  be  devoted  to  rice  growing  unless 
both  preventive  and  corrective  measures  of  radical  nature  are  taken. 
This  injury  may  be  both  to  the  lands  planted  to  rice  and  to  neigh- 
boring lands  in  which  the  ground  water  is  brought  up  through  the 
large  amount  of  water  applied  in  rice  growing.  The  most  important 
preventive  measure  is  to  restrict  rice  growing  to  soils  that  do  not 
require  over,  say,  5  acre-feet  of  water  per  acre  per  annum,  such  as 
the  clay  and  clay  adobes  of  the  Willows,  Capay,  Yolo,  Stockton,  and 
Sacramento  series  already  referred  to  as  being,  so  far  as  observations 
have  gone,  the  most  satisfactory  soils,  from  a  water  standpoint,  for 
rice  growing.  It  can  not  be  too  emphatically  stated  that  the  continued 
growing  of  rice  on  loam  soils  not  underlain  by  an  impervious  stratum 
that  prevents  deep  percolation  of  water  will  result  in  very  great 
damage.  Fortunately,  the  higher  cost  of  irrigating  loam  soils  devoted 
to  rice  will,  as  the  price  of  rice  again  becomes  normal,  tend  to  eliminate 
such  soils  for  this  crop.  Nevertheless,  the  important  corrective  meas- 
ure required — thorough  drainage — should  not  be  delayed;  for  unless 
this  is  provided,  much  injury  will  result  from  only  a  few  years  of 

*U.  S.  Dept.  of  Agr.,  Farmers'  Bull.  1086. 


66  UNIVERSIY   OF   CALIFORNIA EXPERIMENT   STATION 

growing  rice  on  such  land — such  injury  as  already  has  occurred  or 
become  imminent  in  numerous  Sacramento  Valley  rice-growing  sec- 
tions. Thorough  drainage  is  also  of  course  important  in  the  rice 
areas  of  the  heavier  soils,  not  only  to  keep  these  soils  good  for  rice 
and  to  make  the  rotation  of  crops  necessary  for  water  grass  eradication 
possible,  but  also  to  prevent  damage  to  other  lands.  It  is  already 
plain  that  the  drainage  needed  is  much  more  than  that  incident  to 
removing  and  caring  for  the  water  on  the  rice  fields  at  the  close  of 
the  season  when  submergence  is  stopped.  Concerted  neighborhood 
action,  and  not  merely  individual  provision  for  drainage,  will  be 
required  in  carrying  out  both  preventive  and  corrective  measures 
adequate  to  meet  the  menace. 

IRRIGATION    AND    WATER    GRASS 

No  study  of  rice  irrigation  can  overlook  the  great  damage  done 
to  rice  fields  by  water  grass.  At  present,  outside  of  irrigation  and 
drainage,  this  pest  is  the  controlling  factor  in  the  permanence  of 
the  rice  industry  in  California.  It  seldom  does  great  damage  in  the 
first  year  on  new  or  adequately  fallowed  land,  but  with  a  normal 
price  for  rice  three  years  is  practically  the  limit  of  profitable  rice 
growing  until  the  fields  are  again  cleared.  From  an  irrigation  stand- 
point, the  most  important  preventive  measure  to  meet  the  situation 
is  to  keep  the  banks  of  irrigation  ditches,  principally  the  main  and 
field  laterals,  entirely  clean  of  water  grass  either  by  pulling  or  cutting 
out  the  water  grass,  or  by  pasturing  sheep  on  the  ditch  banks  before 
the  seed  has  formed.  Keeping  drains  and  sloughs  free  of  both  water 
grass  and  tules  is  also  absolutely  necessary  if  the  danger  is  to  be 
minimized.  Thus  far  no  satisfactory  mechanical  device  for  removing 
water  grass  seed  from  the  water  in  the  ditches  has  been  devised. 

SUMMARY 

In  43  full-season  measurements  of  the  amount  of  water  used  in  rice 
irrigation  in  Sacramento  Valley,  1914  to  1918,  the  total  depth  of  water 
applied  ranged  from  3.91  to  18.70  feet,  and  the  net  depth,  after 
deducting  measured  or  estimated  waste,  ranged  from  3.91  to  13.43  feet. 

In  32  full-season  observations  on  clay  and  clay  adobes  of  the 
Willows,  Sacramento,  Stockton,  and  Capay  series  the  total  depth  of 
water  applied  ranged  from  3.91  to  10.09  feet,  the  net  depth  from  3.91 
to  9.11  feet,  and  the  average  depth  from  3.94  to  5.72  feet. 

The  average  net  depth  of  water  applied  to  22,404  acres  embraced 
in  the  43  full-season  observations  mentioned  was  4.89  feet.     Of  this 


Bulletin  325 


RICE    IRRIGATION    MEASUREMENTS 


67 


area  21,419  acres  was  clay  or  clay  adobe  of  the  Willows,  Sacramento, 
Stockton,  or  Capay  series. 

A  four-year  record  of  use  on  39.5  acres  of  Stockton  clay  adobe 
near  Biggs,  well  prepared  and  well  irrigated,  showed  a  range  in  depth 
of  water  applied  of  4.27  to  4.87  feet  and  an  average  of  4.53  feet. 

An  annual  depth  of  5  feet  of  irrigation  water  for  rice  is  sufficient 
for  the  principal  rice  soils  of  Sacramento  Valley,  viz :  for  the  clays 
and  clay  adobes  of  the  Willows,  Stockton,  Sacramento,  Capay  and 


Fig.  4. — A  Sacramento  Valley  rice  field  showing  drooping  of  heads  at  the  ripening 
period  when  irrigation  water  is  drawn  off. 


Yolo  series.  Pervious  loam  soils  require  an  excessive  amount  of 
irrigation  water,  and  from  a  water  standpoint  are  not  suitable  for 
rice  growing. 

The  use  on  individual  fields  of  1  cubic  foot  per  second  of  irriga- 
tion water  to  30  to  40  acres  during  the  first  flooding  after  seeding  is 
not  excessive.  Owing  to  the  fact  that  all  growers  are  not  ready  for 
the  first  flooding  at  the  same  time,  canal  diversions  at  this  rate  are 
not  necessary,  although  probably  as  much  as  1  cubic  foot  per  second 
to  about  each  50  acres  served  is  desirable  during  the  period  of  initial 
flooding.  The  seasonal  use  averages  about  65  acres  per  cubic  foot 
per  second. 


68  UNIVERSIY   OF   CALIFORNIA EXPERIMENT   STATION 

About  one-third  of  the  water  applied  to  rice  fields  is  lost  by  evapo- 
ration from  the  surface  of  the  standing  water  during  submergence. 
This  factor  in  the  duty  of  water  cannot  be  controlled. 

A  6-year  series  of  experiments  at  Biggs,  duplicated  for  2  years 
near  Norman,  generally  show  maximum  rice  yields  from  submerging 
rice  fields  6  inches  deep  beginning  30  days  after  emergence  of  the 
plants  above  ground.  An  exception  to  this  was  found  on  the  alkali 
soils  in  the  Norman  plots,  from  which  the  best  yields  were  obtained 
from  submergence  beginning  15  days  after  emergence. 

The  advantage  from  submerging  rice  fields  6  inches  deep  beginning 
30  days  after  emergence  on  all  but  alkali  land,  when  compared  with 
the  results  from  submerging  to  a  less  or  greater  depth  or  beginning 
submergence  earlier  or  later  after  emergence  of  the  plants,  may  not 
average  sufficient  to  offset  the  difference  in  cost  of  irrigation  by  the 
different  methods. 

Constant  movement  of  irrigation  water  through  the  rice  checks 
during  the  period  of  submergence  is  necessary  only  where  the  soil 
contains  alkali  in  sufficient  quantities  to  affect  the  plants. 

Keeping  rice  fields  only  moist  or  "muddy"  throughout  the  grow- 
ing season  gives  reduced  yields  of  poor  quality. 

Fluctuating  depth  of  submergence  may  prove  beneficial  in  rice 
irrigation,  but  experiments  to  date  have,  not  fullly  demonstrated  this 
for  California  conditions. 

It  is  imperative  that  ground  water  and  rise  of  alkali  be  controlled 
in  California  rice  fields  both  by  confining  rice  growing  to  the  heavier, 
impervious  clays  and  clay  adobes,  and  by  thorough  and  adequate 
drainage  facilities  embracing  the  entire  areas  affected  or  likely  to 
be  affected. 

A  prime  factor  in  control  of  water  grass  in  rice  fields  is  the  keeping 
of  banks  of  canals  and  ditches,  principally  lateral  and  field  ditches, 
entirely  free  of  this  pest  by  pulling,  cutting  or  pasturing  before  the 
seed  is  formed.  An  almost  equally  important  factor  is  the  keeping 
of  drains  and  sloughs  free  of  both  water  grass  and  tules. 


Bulletin  325 


RICE    IRRIGATION    MEASUREMENTS 


69 


Appendix 

Summary  of  Gross  Duty  of  Water  Measurements  on  Rice  Supplied  From 

Operation  Records  of  Sacramento  Valley  Irrigation  Companies 

and  Individual  Growers  (Areas  as  Reported  by  Growers). 


Company  or 
grower 

County 

Year 

Total 

area 
for  which 

water 

diverted  or 

supplied 

Soil 
classification 

Average 
quantity  of 
water  div- 
erted per 

acre 
irrigated 

Acres 

Acre-feet 

Yolo  Water  &  Power  Co. 

Yolo 

1915 

300 

Willows  clay  adobe 

6.38 

do 

do 

1916 

7,517 

Willows  clay  adobe 
and  Capay  clay 

6.31 

do 

do 

1917 

12,662 

do 

5.35 

do 

do 

1918 

10,000* 

do 

4.64 

do 

do 

1919 

6,141 

do 

7.75 

Butte  Farm  Land  Co 

Butte 

1919 

1,370 

Stockton  clay  adobe 

4.00 

E.  B.  Copeland 

do 

1919 

830 

do 

4.61 

B.  E.  Crouch 

do 

1919 

2,085 

Clay  loam  and  adobe 

7.53f 

Cbico  Rice  Land  Co 

do 

1919 

1,236 

Stockton  clay  adobe 

5.12 

Clara  Cramer 

do 

1919 

1,391 
260 

do 

5.77 

G.  B.  Randall 

do 

1919 

do 

5.33 

W.  G.  Davis 

do 
do 
do 

1919 
1919 
1919 

622 

370 
1,348 

do 

do 

Stockton  and  Willows 

7. 33  J 

Meikle  Bros 

4.61 

Pacific  Farms  Co 

5.31 

clay  adobe 

Union  Ent.  Co 

do 

1919 

922 

Stockton  clay  adobe 
do 

5.77 

Western  Rice  Growers.... 

do 

1919 

1,578 

4.38 

C.  W.  Kesterson 

do 

1919 

196 

do 

7.24§ 

D.  A.  Sheelove 

1919 

300 

10.73 

Parrott-Phelan 

1919 

3,160 

9.81 

A.  N.  Lewis  Est 

1919 

400 

10.80 

Sutter  Basin  Co 

1919 

7,400 

7.50 

Western  Rice  Growers.... 

Glenn 

1919 

195 

Willows  clay 

5.67 

do 

do 

1919 

90 

Willows  clay  adobe 

7.28 

Samuels  Bros 

do 

1919 

198 

do 

4.49 

Willard  &  Garnett 

do 

1919 

320 

do 

5.91 

Rasmussen 

do 
do 

1919 
1919 

458 
300 

do 
Willows  clay 

4.76 

Tyson 

6.56 

Freed 

do 

1919 

109 

Willows  clay  adobe 

7.66 

Willows  Rice  Co 

do 

1919 

700 

do 

6.71 

Spalding  Ranch 

do 

1919 

2,814 

Willows  clay 

5.79 

*Area  not  all  harvested. 

fLands  badly  cut  up  by  sloughs;  land  more  or  less  lighter  than  adobe. 
t- 

^Excessive  waste  on  this  farm. 


STATION  PUBLICATIONS   AVAILABLE   FOR  FREE   DISTRIBUTION 


BULLETINS 


No. 
168. 

169. 
185. 

208. 
250. 
251. 


252. 
253. 

257. 
261. 
262. 

263. 
266. 

267. 
268. 
270. 


271. 
272. 
273. 

274. 

275. 

276. 
277. 
278. 
279. 
280. 

282. 

283. 


No. 

Observations  on  Some  Vine  Diseases  in  285. 

Sonoma  County.  286. 
Tolerance  of  the  Sugar  Beet  for  Alkali.  288. 
Report  of  Progress  in  Cereal  Investiga- 
tions. 290. 
The  Late  Blight  of  Celery. 

The  Loquat.  297. 

Utilization  of  the  Nitrogen  and  Organic  298. 

Matter    in    Septic    and    ImhofT    Tank  299. 

Sludges.  300. 

Deterioration  of  Lumber.  301. 
Irrigation    and    Soil    Conditions    in    the 

Sierra  Nevada  Foothills,  California.  302. 
New  Dosage  Tables. 

Melaxuma  of  the  Walnut,  "  Juglans  regia."  303. 

Citrus    Diseases    of    Florida    and    Cuba  304. 

Compared  with  Those  of  California. 

Size  Grades  for  Ripe  Olives.  308. 
A  Spotting  of  Citrus  Fruits  Due  to  the 

Action  of  Oil  Liberated  from  the  Rind. 

Experiments  with  Stocks  for  Citrus.  309. 
Growing  and  Grafting  Olive  Seedlings. 

A  Comparison  of  Annual  Cropping,  Bi-  310. 

ennial  Cropping,   and   Green   Manures  311. 

on  the  Yield  of  Wheat.  312. 

Feeding  Dairy  Calves  in  California.  313. 

Commercial  Fertilizers.  314. 

Preliminary    Report    on    Kearney    Vine-  316. 

yard  Experimental  Drain.  317. 

The  Common  Honey  Bee  as  an  Agent  in  318. 

Prune  Polination.  319. 

The  Cultivation   of  Belladonna  in  Cali-  320. 

fornia.  321. 

The  Pomegranate.  322. 

Sudan  Grass.  323. 
Grain  Sorghums. 

Irrigation  of  Rice  in  California.  324. 
Irrigation  of  Alfalfa  in  the  Sacramento 

Valley.  325. 
Trials   with   California   Silage   Crops   for 

Dairy  Cows. 
The  Olive  Insects  of  California. 


The  Milch  Goat  in  California. 

Commercial  Fertilizers. 

Potash  from  Tule  and  the  Fertilizer 
Value  of  Certain  Marsh  Plants. 

The  June  Drop  of  Washington  Navel 
Oranges. 

The  Almond  in  California. 

Seedless  Raisin  Grapes. 

The  Use  of  Lumber  on  California  Farms. 

Commercial  Fertilizers. 

California  State  Dairy  Cow  Competition, 
1916-18. 

Control  of  Ground  Squirrels  by  the 
Fumigation  Method. 

Grape  Syrup. 

A  Study  on  the  Effects  of  Freezes  on 
Citrus  in  California. 

I.  Fumigation  with  Liquid  Hydrocianic 
Acid.  II.  Physical  and  Chemical  Pro- 
perties of  Liquid  Hydrocianic  Acid. 

I.  The  Carob  in  California.  II.  Nutri- 
tive Value  of  the  Carob  Bean. 

Plum  Pollination. 

Investigations  with  Milking  Machines. 

Mariout  Barley. 

Pruning  Yound  Deciduous  Fruit  Trees. 

Cow-Testing  Associations  in  California. 

The  Kaki  or  Oriental  Persimmon. 

Selections  of  Stocks  in  Citrus  Propagation. 

The  Effects  of  Alkali  on  Citrus  Trees. 

Caprifigs  and  Caprification. 

Control  of  the  Coyote  in  California. 

Commercial  Production  of  Grape  Syrup. 

The  Evaporation  of  Grapes. 

Heavy  vs.  Light  Grain  Feeding  for  Dairy 
Cows. 

Storage  of  Perishable  Fruit  at  Freezing 
Temperatures. 

Rice  Irrigation  Measurements  and  Ex- 
periments in  Sacramento  Valley,  1914- 
1919. 


No. 

65.  The  California  Insecticide  Law. 

70.  Observations    on    the    Status    of    Corn 
Growing  in  California. 

76.  Hot  Room  Callusing. 

82.  The     Common     Ground      Squirrels      of 
California. 

87.  Alfalfa. 
109.  Community  or  Local  Extension  Work  by 
the  High  School  Agricultural  Depart- 
ment. 
111.  The  use  of  Lime  and  Gypsum  on  California 
Soils. 

113.  Correspondence  Courses  in  Agriculture. 

114.  Increasing  the  Duty  of  Water. 

115.  Grafting  Vinifera  Vineyards. 

117.  The  Selection  and  Cost  of  a  Small  Pump- 
ing Plant. 
124.  Alfalfa  Silage  for  Fattening  Steers. 

126.  Spraying  for  the  Grape  Leaf  Hopper. 

127.  House  Fumigation. 

128.  Insecticide  Formulas. 

129.  The  Control  of  Citrus  Insects. 

130.  Cabbage  Growing  in  California. 

131.  Spraying  for  Control  of  Walnut  Aphis. 
133.  County  Farm  Adviser. 

135.  Official  Tests  of  Dairy  Cows. 

136.  Melilotus  Indica. 

137.  Wood  Decay  in  Orchard  Trees. 

138.  The  Silo  in  California  Agriculture. 

139.  The  Generation  of  Hydrocyanic  Acid  Gas 

in  Fumigation  by  Portable  Machines. 


CIRCULARS 

No. 


140. 


143. 

144. 
147. 

148. 
152. 

153. 

154. 

155. 
156. 
157. 
158. 
159. 
160. 
164. 
165. 

167. 
168. 


170. 


172. 
173. 


The   Practical   Application    of   Improved 

Methods  of  Fermentation  in  California 

Wineries  during  1913  and  1914. 
Control     of     Grasshoppers    in     Imperial 

Valley. 
Oidium  or  Powdery  Mildew  of  the  Vine. 
Tomato  Growing  in  California. 
"Lungworms". 
Some  Observations  on  the  Bulk  Handling 

of  Grain  in  California. 
Announcement    of    the    California    State 

Dairy  Cow  Competition,  1916-18. 
Irrigation    Practice    in    Growing    Small 

Fruits  in  California. 
Bovine  Tuberculosis. 
How  to  Operate  an  Incubator. 
Control  of  the  Pear  Scab. 
Home  and  Farm  Canning. 
Agriculture  in  the  Imperial  Valley. 
Lettuce  Growing  in  California. 
Small  Fruit  Culture  in  California. 
Fundamentals    of    Sugar    Beet    Culture 

under  California  Conditions. 
Feeding  Stuffs  of  Minor  Importance. 
Spraying  for  the  Control  of  Wild  Morning- 

Glory  within  the  Fog  Belt. 
The  1918  Grain  Crop. 
Fertilizing  California  Soils  for  the   1918 

Crop. 
Wheat  Culture. 
The  Construction  of  the  Wood-Hoop  Silo. 


CIRCULARS — Continued 


No. 

174.  Farm  Drainage  Methods. 

175.  Progress  Report  on  the   Marketing  and 

Distribution  of  Milk. 

176.  Hog  Cholera  Prevention  and  the  Serum 

Treatment. 

177.  Grain  Sorghums. 

178.  The  Packing  of  Apples  in  California. 

179.  Factors  of  Importance  in  Producing  Milk 

of  Low  Bacterial  Count. 

181.  Control  of  the  California  Ground  Squirrel. 

182.  Extending  the  Area  of  Irrigated  Wheat  in 

California  for  1918. 

183.  Infectious  Abortion  in  Cows. 

184.  A  Flock  of  Sheep  on  the  Farm. 

185.  Beekeeping  for  the  Fruit-grower  and  Small 

Rancher  or  Amateur. 

187.  Utilizing  the  Sorghums. 

188.  Lambing  Sheds. 

189.  Winter  Forage  Crops. 

190.  Agriculture  Clubs  in  California. 

191.  Pruning  the  Seedless  Grapes. 

193.  A  Study  of  Farm  Labor  in  California. 

195.  Revised  Compatibility  Chart  of  Insecti- 
cides and  Fungicides. 

197.  Suggestions  for  Increasing  Egg  Produc- 
tion in  a  Time  of  High-Feed  Prices. 


No. 

198.  Syrup  from  Sweet  Sorghum. 

201.  Helpful  Hints  to  Hog  Raisers. 

202.  County     Organization     for     Rural     Fire 

Control. 

203.  Peat  as  a  Manure  Substitute. 

204.  Handbook    of   Plant    Diseases   and    Pest 

Control. 

205.  Blackleg. 

206.  Jack  Cheese. 

207.  Neufchatel  Cheese. 

208.  Summary  of  the  Annual  Reports  of  the 

Farm  Advisors  of  California. 
210.  Suggestions  to  the  Settler  in  California. 

213.  Evaporators  for  Prune  Drying. 

214.  Seed    Treatment   for   the    Prevention    of 

Cereal  Smuts. 

215.  Feeding  Dairy  Cows  in  California. 

216.  Winter  Injury  or  Die-Back  of  the  Walnut. 

217.  Methods    for    Marketing    Vegetables    in 

California. 

218.  Advanced  Registry  Testing  of  Dairy  Cows. 

219.  The  Present  Status  of  Alkali. 

220.  Unfermented  Fruit  Juices. 

221.  How  California  is  Helping    People   Own 

Farms  and  Rural  Homes. 


